Fujitsu’s F-Series flip phone is nicknamed the “uwaki keitai” or “infidelity phone” in Japan, where it is used by customers trying to hide their illicit romances.
The model has built-in stealth features that help users stay discreet, with a ‘privacy mode’ that hides all incoming calls, texts, and emails from any contact marked as private. This means that even if someone checks your phone they won’t find anything suspicious. Instead, a subtle change in the color or shape of the battery signs or signal bars alerts the owner that an ‘acquaintance’ has been in touch.
The privacy mode can be turned off using a secret combination of keys, which reveals the hidden calls and messages. The Wall Street Journal writes that the phone is useful for Japanese philanderers like the blogger “Poza”:
He claims to have various romances on dating sites while juggling three girlfriends. He said he was introduced to the Fujitsu phone nearly five years ago and uses the privacy features to keep from getting caught. He says he recently bought an iPhone, but giving up his Fujitsu phone to carry just a smartphone is “unthinkable.”